Toward a new dark-energy detector

Fermilab is working toward the development of a new instrument for detecting dark energy based on MKID sensors. MKIDs are superconducting detectors and must be operated very cold. Here, two team members, Kevin Kuk and Donna Kubik, check the temperature on the cryostat, which contains the prototype MKID. Photo: Reidar Hahn

The power of the 570-megapixel Dark Energy Camera lies in its ability to capture celestial objects millions of light-years away. Scientists are now working toward developing an instrument for characterizing these stars and galaxies in greater detail.

Scientist Juan Estrada, PPD, is currently leading a Fermilab team to develop a large instrument using detectors called MKIDs, short for microwave kinetic inductance detectors. In the coming years, they'll use it to obtain more information about the astronomical objects already detected by the Dark Energy Camera, pointing it into the night sky to capture more information about those objects' light.

The team builds on the work of a University of California, Santa Barbara group, led by Ben Mazin, which developed MKIDs for the visible and infrared spectrum.

"These are small detectors," Estrada said. "We'd like to convert this technology into something for a large instrument for cosmology."

The Dark Energy Camera is outfitted with 74 charge-coupled devices, better known as CCDs, and its optical filters divide the light from far-off galaxies or stars into one of five spectral ranges. When a CCD gets a hit from one of the photons from the split-off light, it sends a small signal saying that the light in that filter's range of wavelengths has come through. The data from the five filters are then reassembled into a color picture of the galaxy or star, much the way your computer monitor layers red, green and blue pixels to generate full-color images.

An MKID, however, would enhance that five-color rendering many times over. When struck by a visible photon, it produces a flood of so-called quasiparticles, allowing the wavelength for every single photon hitting the MKID to be precisely measured. That, in turn, leads to color images of astronomical objects without the use of optical filters. The higher the photon's energy — or the more towards the violet end of the spectrum it is — the more particles it produces.

MKIDs, which use superconducting material, must be very cold to be able to detect photons. In testing the current MKID-based prototype instrument, Estrada's team recently brought it to a temperature of 33 millikelvin — the lowest temperature ever achieved on site at Fermilab.

Over the next several years, the team hopes to create an MKID prototype instrument that can be installed in a telescope on a mountaintop next to DECam for testing. This means assembling it with a compatible mechanical design and high-bandwidth digital processing system.

If all goes well, they can look realistically to constructing instruments installed with MKIDs and, conceivably, with 100,000 light channels. That's 20 times more channels than the next-generation technology represented by the Dark Energy Spectroscopic Instrument, a future spectrograph that Fermilab is now helping to construct.

"We are still some distance away from having a full-on instrument," Estrada said. "But we are taking the initial steps that would put us closer to this very ambitious goal."

IceCube neutrino detector is running hot

From ars technica, Jan. 23, 2014

With the IceCube detector now in operation at the South Pole, the first results are starting to come in, and boy are they interesting. IceCube monitors a volume of one cubic kilometer of ice for muons, the byproduct of neutrinos colliding with the ice. What makes IceCube different is that it is looking especially for very high energy neutrinos. In the lower energy range, neutrinos are products of things generated very locally (in astronomical terms). Although these events are interesting, they swamp those that are produced at great distances, making it difficult to use neutrinos as a window into the universe.

Scientists: Cosmic rays can see through nuclear reactor, locate fuel

Japanese scientists have developed a method to use cosmic rays to see through a nuclear reactor, raising hopes for locating and accounting for melted fuel inside the crippled Fukushima nuclear plant.

"Installing several sensors outdoors for a month or so is enough to get a picture of internal structures," said Fumihiko Takasaki, a particle physics scientist at the High Energy Accelerator Research Organization. "Our technology is well established, so I hope it will be used to help decommission the stricken reactors at the Fukushima No. 1 nuclear power plant."

Getting the most out of Fermilab's accelerators

Associate Directorfor AcceleratorsStuart Henderson

While the high-energy physics community focuses on the 10- to 20-year plan for the field in the P5 planning process, we find ourselves quite busy in the here-and-now delivering on our commitments to our user community.

With the completion of the long accelerator shutdown in early September — the most substantial reconfiguration of the Fermilab accelerator complex since the Main Injector was built — the Accelerator Division has been focusing on recommissioning the machines to increase the beam power delivered to the NuMI beamline for the NOvA experiment. Our plans call for doubling the beam power delivered to NuMI, increasing our pre-shutdown power level of 350 kW to 700 kW.

Doubling the beam power is an ambitious and challenging task that will demand the attention and focus of many within the accelerator sector. The recommissioning of the Recycler ring, under way right now, will allow the accumulation of high-intensity beam in that accelerator, prior to the beam's acceleration to high energy in the Main Injector.

Further demand for Fermilab's proton beams have motivated our plans for the Proton Improvement Plan and the Muon Campus. The goal of PIP is to double the beam flux from the Booster while increasing the long-term reliability of the proton source. These improvements, together with the Muon Campus reconfiguration, will support the field's plans for the Muon g-2 and Mu2e experiments, which will come online in a few years. Carrying out these challenging improvements requires the focus and attention of many of us at the laboratory.

While these improvements will give us leading capabilities for the near-term accelerator-based particle physics program, it is clear that higher proton intensities are required to meet the future demands of next-generation experiments. To that end, planning for PIP-II is under way. PIP-II will provide beam intensities that are unmatched and, at the same time, provide a platform from which to build the particle physics accelerators of the future.

These are ambitious plans that will position Fermilab at the forefront of Intensity Frontier accelerators for particle physics. These improvements and upgrades build upon the substantial investment in Fermilab's infrastructure over the last 40-plus years to deliver world-leading beam intensity and beam power in the most cost-effective way possible.

Thanks to all of you who are working so hard to get the most out of Fermilab's accelerators.

Photos of the Day

Bright spots in the cold

Several photographers at Fermilab snapped pictures of yesterday's sundogs over the laboratory grounds during the -5 Fahrenheit cold. Photo: Ed Dijak, PPD

Sundogs frame Wilson Hall. Photo: Charles King, AD

A full circle of sundogs fills the space in the sky next to the high-rise. Photo: Lynn Garren, SCD